1. Field of the Invention
The present invention relates to a moving picture converting apparatus and method and a computer program. More particularly, it is directed to a moving picture converting apparatus and method and a computer program, capable of reconstructing an image from image data compressed by thinning.
2. Description of the Related Art
Moving-picture data is converted to reduce its size, namely, it is compressed, for storage in a storage medium such as hard disk, DVD or the like or for distribution over a network. Recently, the size of moving-picture data has drastically been increased along with an improvement in the quality of moving picture data. One of such picture data is the high-definition data. In these circumstances, many studies and researches have been made as to the compression of moving picture data, the improvement of the data compression ratio in image reconstruction, and the prevention of deterioration of reconstructed images.
A moving picture can be compressed by, for example, a thinning of pixels of picture frames included in moving picture data, that is, space-directional thinning of the pixels, and a reduction of the frame rate, that is, time-directional thinning of the pixels, etc.
Advantageously, moving picture data can efficiently be stored in a storage medium or transferred via a network owing to a data-amount reduction by such data conversion. When the compressed data is restored and reproduced, however, the image quality will be deteriorated. Especially, in the case where the original data is a high-definition picture, the image deterioration will be more noticeable.
Various studies have been made on how to minimize the image deterioration. For example, the Japanese Patent Laid-Open No. 2003-169284 discloses an image compression in which a parameter is set based on the brightness of an image and the manner of compression is varied depending upon the image brightness. Also, the Japanese Patent Laid-Open No. 2002-27466 discloses an image compression in which a scene is divided into a plurality of blocks and the manner of compression is varied for each of the blocks.